The present invention generally relates to an optoelectronic transceiver and more particularly, relates to an optoelectronic transceiver that can be passively aligned by a flip-chip method wherein transceiver has integrated optical and electronic components.
The use of optoelectronic technology such as those related to optical data storage and retrieval for computer applications has been growing rapidly in recent years. For instance, it is used in a typical optical data storage device, such as a compact disk. It has also found many other uses in consumer-oriented products, including home entertainment systems, multi-media systems, CD ROM for computer memories and other sophisticated computer devices. Optical disk memories have also emerged as an important and reliable form of information storage for computer systems in general. An optoelectronic transceiver is a key component within such systems.
An optoelectronic transceiver typically includes a laser diode and a photo diode that are used to transmit light in a manner that allows the information from an optical disk to be retrieved. The optoelectronic transceiver typically includes an array of microlenses and a compact optical system that collect and process light that originates from a laser diode that is reflected from the disk surface. A set of photodetectors are utilized to convert reflected light into electronic signals in order to gather the information that is stored on the optical disk. Photodetectors are also used to ensure that the light emitted from the laser diode is focused and tracked properly.
To allow an optoelectronic transceiver to function properly in an optoelectronic system, the geometric and alignment requirements of the system must be met. The geometric requirements, which include the packaging of the various components in a small, compact package such that the size of the optoelectronic device can be reduced. The alignment requirements inbetween the optical source, the microlens and the laser diode is also critical such that the optical signals can be fully converted to electronic signals without the possibility of inaccurate processing of information from the optical disk.
It is therefore an object of the present invention to provide an optoelectronic transceiver that does not have the drawbacks or shortcomings of the conventional optoelectronic transceivers.
It is another object of the present invention to provide an optoelectronic transceiver that has integrated optical and electronic components that form a compact package.
It is a further object of the present invention to provide an optoelectronic transceiver wherein the optical source, the microlens and the laser diode are passively aligned by a flip-chip method.
It is another further object of the present invention to provide an optoelectronic transceiver that has integrated optical and electronic components assembled on a circuit board and in a receptacle.
It is still another object of the present invention to provide an optoelectronic transceiver that utilizes a plurality of wirebonds electrically connecting a silicon sub-mount to a circuit board, and at least two IC chips to the silicon sub-mount.
It is yet another object of the present invention to provide an optoelectronic transceiver that utilizes solder bumps by a self-aligned flip-chip method for connecting electrically of at least two IC chips to a silicon sub-mount.
It is still another further object of the present invention to provide an optoelectronic transceiver wherein self alignment between a silicon sub-mount and a microlens array is achieved by using mechanical means of spacer balls and indentations provided in the surfaces of the silicon sub-mount and the microlens array.
In accordance with the present invention, an optoelectronic transceiver that has integrated optical and electronic components, and is passively aligned by a flip-chip solder bump method is provided.
In a preferred embodiment, an optoelectronic transceiver that has integrated optical and electronic components is provided which includes a circuit board that is formed in an xe2x80x9cLxe2x80x9d shape with a vertical portion and a horizontal portion. The vertical portion has an exterior planar surface for receiving a silicon sub-mount. The horizontal portion has a bottom surface provided with a plurality of conductive leads; a silicon sub-mount for mounting to the exterior planar surface of the vertical portion of the circuit board; at least two IC chips of a laser diode and a photodetector formed on a top surface of the silicon sub-mount; an array of microlenses positioned juxtaposed and parallel to the silicon sub-mount aligned with the laser diode; an optical fiber for inputting or outputting an optical signal through an optical fiber connector; and a receptacle for housing the silicon sub-mount, the at least two IC chips, the array of microlenses and the optical fiber connector in an aligned configuration.
The optoelectronic transceiver that has integrated optical and electronic components may further include a heat spreader positioned on a top surface of the horizontal portion of the circuit board. The transceiver may further include a plurality of wirebonds electrically connecting the silicon sub-mount to the circuit board, and electrically connecting the at least two IC chips to the silicon sub-mount. The at least two IC chips may further include solder bumps for providing electrical communication with the silicon sub-mount. The at least two IC chips may be self-aligned with the silicon sub-mount by a plurality of solder bumps. The optoelectronic transceiver may further include at least four indentations formed in a top surface of the silicon sub-mount and in a bottom surface of the array of microlenses in such a way that the indentations are mirror imaged to each other when the silicon sub-mount and the array of microlenses are in an assembled position, and at least four spacer balls positioned in-between the at least four indentations to self-align the silicon sub-mount to the array of microlenses.
In the optoelectronic transceiver, the circuit board may be formed of an insulating material. The at least two IC chips may be four IC chips that includes a laser diode, a photodetector, a laser diode driver and a photodetector amplifier. The at least two IC chips may further include wirebonds for providing electrical communication with the silicon sub-mount. The optoelectronic transceiver may further include at least two spacer bars positioned between the array of microlenses and the silicon sub-mount for keeping a predetermined spacing between the array of microlenses and the at least two IC chips. The plurality of conductive leads on the bottom surface of the horizontal portion of the circuit board may be a plurality of solder bumps.
In the optoelectronic transceiver, the receptacle may be formed of a top plate, a bottom plate, a mounting column on each of the top and bottom plates and an aperture at a center of each of the mounting columns for receiving a pair of guide pins when the optoelectronic transceiver is in an assembled position. The vertical portion of the circuit board may further include a pair of apertures at near a top and a bottom edge of the vertical portion for receiving a pair of guide pins. The pair of guide pins may engage a pair of apertures in the vertical portion of the circuit board at one end, while engaging a pair of apertures in the mounting columns at the other end. The optical fiber may include a bundle of optical fibers. The silicon sub-mount, the at least two IC chips and the array of microlenses are positioned parallel to each other when they are mounted in the receptacle. The laser diode may be one that generates pulsed laser.